Alternating-current motor.



PATENTED MAY 28, 1907.

M. o. A. LATOUR. ALTBRNATING CURRENT MOTOR.

APPLICATION FILED JUNE18,1904

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PATENTED MAY 28, 1907.

0. A. LATOUR. ALTBRNATING CURRENT MOTOR.

APPLICATION FILED JUNE 18. 1904.

2 SHEETS-SHEET 2.

Witnesses Inventor.

Marius Charles firth urLatpur. by Gila/1 rent motors of the commutator type, and its UNITED s'rngrns PATENT oFFIoE.

MARIUS C. A. LATO UR', OF PARIS, FRANCE, ASST 1N0? TO GENERAL ELECTRIC COMPANY, A CORPURATION OF NEW YORK.

ALTERNATING GURRENT MOTOR.

Specification of Letters Patent.

Patented. May 28, 1907.

Application filed June 18,1Q04. Serial-No. 218,056.

To aZZ whom it may concern:

Be it known that I, MARIUS C. A. LATOUR,

- a citizen of France, residing at Paris, France,

. 01 which the following is a specification.

My invention rela'testo alternating-cur object is to provide a novel arrangement and control for such a motor whereby it is enabled to start with the hightorque of a re pulsion motor, and to operate at practically constant speed like a shimt or an induction motor.

The ordinary repulsion motor, the stator of which is provided with a distributed wind ing to which the rotor being short-circuited on a ue at an angle to the fieldmagnetization, has an excellent starting torque and works very well in the neighborhood of synchronous speed as far as commutation is concerned, but its oporation is not stable as regards speed. A

slight change in load produces alar'ge change in its's'peedyand when the "speed rises much above synohronism severe sparking is produced. Consequently this motor is not very suitable for working at constant speed under .variahleload. The single-phase induction.

m0.tor,' on the other hand, has no starting torque, hut'operates at substantially con stant speed under all loads, and the shunt motor, which has little starting torque, is

also 'a' suhstanti ally constant-speed motor.

My present invention consists in providing proper connections for starting a motor as a repulsion motor, together with suitable controlling means for transforming it into a constant-speed motor, such as a shunt or in duction motor, when up to speed.

' My invention will'bestbe understood by reference to' the'accompanying drawings, in which I Figure 1 shows diagrammatically a motor arranged in accordance with my invention; Fig. 2 shows a modification of the same, 111 which the motor may be connected as a shunt motor when up to speed; Fig. 3 shows a modification in which a polyphase excita-- tion is employed for the rotor; and Fig. 4

shows a modified arrangement of the com mutator brushes and their connections.

In Fig. 1, S represents an ordinary stator with a distributed winding, theternunaisofsingle-phase current is supplied,

which are connected through the switch 8 to the source of single-phase current a a. currentin the winding of stator S produces a magnetization on the line of the stator terminals. It represents the rotor, which. is rovided with the commutator O on which ear two sets of brushes 6 b andb b. Each set of brushes is short-circuited,- the shortcircuits being'on parallel lines at an angle to the line of magnetization of the stator. The motor consequently starts as an ordinary repulsion motor. When the motor is up to speed, the switchs' may be closed, thereby interconnecting the two short circuits. This establishes two more closed circuits on par- 1 allel lines at an angleto the first. Four points on therotor winding are now electrically connected to each other, and the motor acts as'a singlephase induction motor. 'The resistance?" is. provided in the circuit connecting the two short circuits, so that "the change from the repulsion motor action to the induction motormay be gradual. This resistance may be gradually cut out after the switch a has been closed.

instead of directly short-circuiting the two short-circuiting connections, the connection between them. may be made through a source of voltage. Thus, in Fig. 2 I.l1ave shown the switch a interconnecting the two short-circuits through the secondary of the transformer T. The primary of the transformer may be connected to any suitable source of current, and in this case I have shown it connected to extra terminals on the stator wind- .;ing which are selected, as regards their osicontrolled by the switch .9 is employed for producing a gradual transition.

Instead ol 'the snunt excitation shown in 2, a polyphase excitation may be employed on the rotor, if desired. Thus, in Fig 3 1 have shown the brushes b short-cucuited through an amiiliary c'oil Dion the stator.

The

- through these coils.

The brushes 1) are short-circuit'ed through a similar coil D The electromotive forces of the coils D and D are small compared to the induced electromotive force in the winding at starting, so that at startingthe effect is the same as though the brushes were directly short-circuited, as inthe former figures. Two other auxiliary coils D and D are provided, together with switches d and d, by means of which each coil may be connected between a brush 1) and a brush b, so as to short-circuit tn sets of brushes on each other I circuited through a source of polyphase excitationwhich serves to improve the efficiency and power factor of the motor when the motor is up to speed. Instead of obtaining the polyphase excitation from auxiliary coils on the stator, it obviously may be obtained from any suitable source of polyphase voltage, as

from auxiliary field terminals.

'ments may be employed.

Although in the arrangements shown heretofore, the rotor has been short-cir'cuited at the start on two parallel lines at an angle to the line of magnetization of the primary member, it is obvious that other arrange- Fig. 4 I have shown the rotor with its commutator brushes arranged so as to produce only a single short-circuit at'the start. A second set of brushes 1) b are displaced approximately degrees from the first set, and the switch 8 is arranged to close the circuit of these brushes and thereby to .close the rotor circuit on a second line at an angle to the first through a source of potential in the same manner as in the arrangement of Fig. 2. The operation with this arrangement of brushes is practically the same as the'operation with the two parallel short-circuits, exceptthat since the induced voltage at the brushes is greater with the arrangement of Fig. 4, the commutation is not as good as in the arrangement of the former figures. Instead of clos ing the circuit of the brushes 1) in Fig. 4 through a source of shunt excitation, evidently a simple short-circuit may be em ployed for these brushes, or a .polyphase excitation may be used with this arrangement of brushes, as in Fig. 3.

Although in the drawings I have merely indicated diagrammatically the switch for The rotor is thus short- For instance, in,

ingly I do not desire to limit myself to the particular construction and arrangement of parts shown, and I aim in the appended claims to cover all such modifications which are within the scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. In an alternating-current motor, adistributed primary winding, a secondary winding provided with a commutator, means for closing the circuit of the secondary winding field magnetization, and means for closing second line at an an le to the first when the motor is up to speed.

' 2. In an alternating-current motor, 'a distributed rimary winding, a secondary winding IOVldGd with a commutator, means for closmg the circuit of the secondary at starting on a line at an angle to the line of field magnetization, and means for closing the ,circuit of the secondary winding through a source of voltage on a second line at an angle to the first when the motor is up to speed.

3. In an alternating-current motor, a dis tributedprimary winding, a secondary winding provlded with a commutator, means for closing the circuit of the secondary Winding at-starting on a line at an angle to the line of. field magnetization, and means for impressing a voltage on the secondary winding on a line at an angle to the first when the motor is up to speed.

4. In an alternating-current motor, a dis-- tributed primary winding, a secondary winding provided with a commutator, means for closmg the circuit of thesec'ondary winding at starting on a line at an angle to the line of field magnetization, and means'for impressing a shunt excitation on the secondary winding on a line at an angle to the first when thc motor is up to speed.

5. In combination with an alternatingcurrent motor of the commutator type, means for connecting it at the start as a repulsion motor, and means for connecting it as a shunt motor when it is up to s eed.

6. In combination with an a ternatingcurrent motor of the commutator type, means for short-circuiting the rotor to cause means for establishing additional connections from the rotor to source of voltage to cause the motor to operate as a'shunt motor.

7. In an alternating-current.motor, a distributed primary winding supplied with alternating-current, a secondary member provided with a distributed winding connected at intervals to the segments of a many-part commutator, brushes bearing on said commutator, connections for short-circuiting the secondary winding through the'brushes on a line at an angle to the line of the field magnetization, connections for feeding an excitat starting on a line at an angle to the line of x the circuit of the secondary winding on a the motor to start as a repulsion motor, and

ing current through said brushes on a line displaced substantially 90 electrical degrees from the line of the short-circuit, and a switch in the circuit of the latter connections for opening the circuit at starting and closing it at normal speed 8. In an alternating-current motor, a distributed primary Winding, a secondary winding provided with a commutator, brushes bearing on said commutator and arranged and connected to short-circuit said secondary winding on parallel lines at an angle to the field magnetization, and means for interconnecting the parallel short-circuits when the motor has started.

9. In an alternatin -current motor, a distributed primary win ing, a secondary winding provided with a commutator, brushes bearing on said commutator and arranged and connected toshort-circuit said secondary winding on parallel lines at an angle to the field magnetization, and means for 1nterconnectin the parallel short-circuits through a source 0 voltage.

10. In an alternating-current motor, a distributed .primary winding, a secondary winding provided with a commutator, brushes bearing on said commutator and arranged and connected to short-circuit said secondary winding on parallel lines at an angle to the field magnetization, and means for connecting the parallel short-circuits to a source of shunt excitation.

11. In an alternating-current motor, a distributed primary winding, a secondary winding provided with a commutator,

brushes bearing on said commutator and ar-.

ranged and connected to short-circuit said secondary winding on parallel lines at an angle to the field magnetization so as to start the motor as a repulsion motor, and means for interconnecting the parallel shortcircuits through a source of shunt excitation so as to operate the motor as a shunt motor.

12. In an alternating-current motor, a distributed primary winding, a secondary winding provided with a commutator, four' commutator brushes per pair of poles arranged and connected in pairs so as to form two parallel short-circuits at an angle to field magnetization, and means for connecting said parallel short-circuits to a source of voltage.

13. In an alternating-current motor, a distributed primary winding, a secondary winding provided with a commutator, four brushes per pair of poles bearing on said commutator and arranged and connected in pair so as to form two parallel short-circuits at an angle to the field magnetization, and means for supplying to the secondary Wind'- ing through said short-circuiting connections a current derived from the field.

14. In combination, a repulsion motor having two sets of commutator brushes, said sets being displaced from each other by approximately 90 electrical degrees and both sets bein displaced from the line of magnetization of the primary member, means for short-circuiting one set, and means for closing the circuit of the other set through a source of compensating electromotive force when the motor is up to speed.

15. In combination, a repulsion motor having two sets of commutator brushes, said sets being displaced from 'each other by ap proximately 90 electrical degrees and both sets being displaced from the line of magnetization of the primary member, means for short-circuiting one set, and means for impressing a variable voltage on the other set.

16. In combination, a repulsion motor having two sets of commutator brushes, said sets being displaced from each other by approximately 90 electrical degrees and both sets being displaced. from the line of magnetization of the primary member, a source of voltage, and a switch adated to close the circuit of the second setot brushes through said source when the motor is up to speed.

17. In combination, a repulsion motor having two sets of commutator brushes, said sets being displaced from each other by approximately 90 electrical degrees and both sets being displaced from the ine of magnetization of the primary member, means for short-circuiting one set, and means for connecting the second set to a portion of the Winding of the primary member of the motor.

In witness whereof, I have hereunto set my hand this 16th day of June, 1904.

MARIUS O. A. LATOUR.

Witnesses:

EDWARD WILLIAMS, J12, L. A. HAWKINS. 

